The period of support of this Cooperative Agreement was from April 15, 1990 to October 31, 1992, with a no-cost extension to October 31, 1993 to complete some unfinished tasks. Within this period, research associate Dr. Kai-Hsiung Kao has made tremendous contributions to this project and has produced an impressive amount of publications. At the early stage of the research, he spent some time on the extension of his doctoral thesis in a subject closely related to the present project. His major research effort was devoted to the investigation of stability of a viscous flow between two differentially rotating cylinders, with an emphasis on the effects of compressibility and heat transfer. Actually, the research topics were not restricted to those described by the title of this Agreement, as reflected in some of the more recent publications.